Care should be taken to keep the skin and gums of the mouth intact and free from bleeding. It is helpful to avoid behaviors such as eating crispy foods, like chips, and hot foods, like melted cheese, which can wound the inside of the mouth. Partners are advised to postpone oral sex for several minutes following brushing or flossing, as both can irritate the gums.

If a lesion, open wound, or pus is found on the penis or opening (meatus), it may be better to keep it out of the mouth. The inability to achieve an erection may also be a sign of STD. If this occurs in a partner who feels ill, it may be best to avoid oral sex. Avoiding genital herpes, genital warts, and molluscum is harder because the lesions can be difficult to see. For example, molluscum often affects the pubic area and may be hidden beneath hair. Oral contact with these lesions, whether they are visible or not, can lead to infection.

The STDs most commonly associated with oral-anal sex are hepatitis A and parasitic infections. Men who have sex with men are advised to get a hepatitis A vaccination, which consists of two shots given 6 to 12 months apart. Parasitic infections are treated with oral antibiotics. The best preventive practice is to wash the anal region thoroughly before oral-anal sex.

Oral-anal sex, oral or anal role, with a dental dam
If a dental dam is used properly during oral-anal sex, there is no risk for contracting STDs. A dental dam is a piece of plastic or latex that is laid over the anus prior to oral-anal contact. It creates a barrier that prevents the spread of STDs. Applying a small amount of water-based lubricant to the anus before placing the dental dam on it enhances pleasure. Ordinary plastic wrap can be used as a dental dam as long as it is not the microwavable kind, which is porous. Dental dams are available in most stores that carry condoms.